Fuse plug



Aug. 15, 1933. R, OLANDT FUSE PLUG Filed Nov. 25, 1931 INVENTOR Robe/ t Olandi BY H/S ATTO? patented Aug. 15, 1933 FUSE PLUG Robert H. Olanclt, Long Island. city. N. Y.

Application November 25, 1931 Serial No. 577,202

2 Claims.

Among the principal objects which the present invention has in view are: To provide a fuse plug having a plurality of fusible elements, one of which may be replaced when desired; to provide a fuse plug having means therein for carrying a supply of reserve fusible elements; to provide a slidable cover which may be opened when desiring to replace a fusible element with a new one; to provide means to indicate when a fusible element has been blown; to provide means to securely hold a fusible element thereto; to secure simplicity of construction and operation; and to obtain other advantages and results as may be brought out in F the following description.

proved fuse plug and embodying my invention;

Figure 2 is a plan view looking down on top of Figure 1;

Figure 3 is a sectional view taken on the line 3-3 of Figure 1;

Figure l is a plan of a fusible element;

Figureb is a perspective view of one of the fusible element supports, and

Figure 6 is a modified form of fuse plug.

In the specification:

In the specific embodiment of the invention illustrated in said drawi g, the reference numeral 10 indicates a fuse plugof thetype adapted to be screwed into a socket with an outer enlarged end projecting from the socket. inner end of the plug provides a central contact member 11, whereas the peripheral margin of the inner portion of the plug is provided with a metallic threaded collar or ferrule 12 by which the device may both be screwed into place and obtain an electrical contact with the socket. The contact 11 and the ferrule 12 are electrically separated by the body material compressing the plug which is of an insulatory character. Within the middle interior of the plug is a fuse chamber 13 containing a fusible element or wire 14 attached at its lower end to the contact 11 and at its upper end to a strip 15 which forms a fusible element support; The

device is preferably so constructed that access The (Cl. i3121) other end of said chamber is positioned the upperend of another strip or fusible element support 17. A fusible element 18 lies within the chamber and extends from one support 15 to the other support 1'? both mechanically and electrically connecting the same. tioned strip 17 extends downwardly within a hole 19 and is positioned at'its lower end between the outer Wall of the body material and the farrule 12 so as to be securely mounted and so as to obtain desired electrical contact between the strip and ferrule. It will accordingly be observed that when thefuse plug is in use, current will flow from the central contact 11 through the main fusible element 14 to the fuse support 15, through the secondary fusible elementlS and its other support 1'7 to the ferrule 12, thus mak ing a complete'circuit as is usual in fuse plugs The secondary fusible element 18 isshown in Figure 4 as having a perforation 20 adjacent each end thereof, and theupper ends of the strips 16 and 17 each have a projecting finger or portion 21 adapted to enter the said perfora- The second mention. lhe said strips likewise provide upwardly projecting shoulders 22 for limiting the down' ward movement of the fusible element when "applying the same to said strips. The fingers 21 preferably lean away from each other so that the tendency of the fingers to'move apartjwill operate to draw the fusible'element downwardly against said shoulders. By preference, the strip 1'? positioned in hole 19 and secured by'ferrule 12 is of a resilient charactennormally tending to swing away from the other strip 15. As a result, the fusible element 18 will be under tension and will draw the flexible strip 17 out of normal position. The fusible element 18 may be i perforated as at 23 with a hole of appropriate size to obtain the desired cross-section capable of carrying the current for which the fuse is cross-section, at which time obviously no further current can pass and because of the severance of the fusible element, the strip 17 is permitted to swing back to its normal position.

I preferably provide means for indicating on the outside of the plug that the fuse is burned f out, and in carrying outthis feature of the invention, I attach a signal to the resilient strip 17, and make the signal visible upon the exterior of the plug. As here shown, the signal comprises a plunger 24, the inner end of which is secured socket. 'usual fusev chamber containing a fusible elesecondary fusible element 18 through the side wall of the plug so that its outer end may project radially from an upper part of the plug.

The parts are preferably so proportioned as to retract the outer end of the signal or plunger to a position substantially flush with the surface of the plug when the spring strip 1'7 is drawn toward the other strip by the secondary fusible element. However, when the fusible element is removed or becomes severed permitting the spring strip 17 to swing outwardly, the plunger is moved outwardly likewise-and the outer end will then project and call attention to the fact that the plug is inoperative for electrical conductive purposes. It may be noted that the secondary fusible element 18 is preferably fusible with less current passing therethrough than the primary fusible element '14. Under normal conditions, therefore, the secondary element 18 will burn out under excessive load and the primary fusible element will not be affected.

In order that secondary fusible element 18 may be replaced, the chamber 16 within which the element is positioned in use is provided with a removable closure such as a slide 26. As here shown, the slide is arranged transverse to the general axis of the plug and is slidably removable only in one direction. The inner end of the slide is shownoverlying a pocket 27 extending downwardly in the body of the plug, this pocket being adapted to receive one or more secondary fusible elements 18 as reserve elements to be withdrawn and applied to the strips as found necessary or desired. The slide is furthermore shown of a thickness adapting it to also provide a pocket 28 therein for receiving other reserve elements.

Referring now to Figure 6, I have shown a fuse-plug having the usual central contact member 11 and a metallic threaded-collar or ferrule 12 by which the device may be screwed into place and obtain an electrical contact with the Said fuse plug is provided with the ment, which in this instance may likewise be utilized as a spring meiner 28 Said spring. -member 28 is attached at its lower end to the end of which passes to within the fuse chamber and attached to the spring member 28 as by being soldered thereto as at 30. The upper part of the spring member 23 is of a flattened strip 31 and preferably of the same diameter of the opening 32 in the top of the fuse plug. This flattened strip may in this instance be termed as an indicator should the fusible element 31 be blown at any time by carrying a current in excessof the desired amount, said member will fuse or melt at the connecting point 30, thereby causing the spring member 28 to swing away and the indicator 31' will then register with the opening 32, said indicator 31 will then be in view to an observer and the blown fuse plug may therefore be easily located and be replaced.

I claim:

1. A device as characterized comprising a body portion having a chamber therein for a replaceable fusible element, a pair of upstanding members in substantially parallel relationship to each other within said chamber, said upstanding members being provided with means at their upper ends for receiving said fusible element, and means extending inwardly from the outside of the body portion and attached to one of said upstanding members for aligning and positioning said member when the fusible element is to be attached thereto, and said body being provided with a slidable cover to be removed when replacing the fusible element with a" new one.

2. A device as characterized comprising a body portion having a chamber therein for a replaceable fusible element, a pair of upstanding members in substantially parallel relationship to each other, within said chamber, said upstanding members being provided with means at their upper ends for receiving said fusible element, and means extending inwardly from the outside of the body portion and attached to one of said upstanding members for aligning and positioning said member with respect to the other said member when the fusible element is to be attached thereto, said means to spring outwardly when the fusible element has been blown, thereby indicating disconnection, and said body being provided with alslidable cover to be removed when replacing the fusible ele-- ment with a new one.

ROBERT H. OLANDT. 

